Sylvan seizures belong to the Rolandic Epilepsy Syndrome. The abnormal brain activity takes place in the part of the brain known as the rolandic strip.
These tend to be nocturnal seizures only and the characteristics of them are predominantly present in one lower half of the face. Seizures last no more than two minutes and consciousness is maintained throughout. Symptoms include: jerking, twitching, numbness, all of which can affect the tongue which in turn may cause problems with speech and subsequent drooling.
This condition is frequently outgrown by adulthood.